Epitalon: A Synthetic Tetrapeptide and the State of Its Evidence

Epitalon — also transliterated epithalon or epithalone — is a synthetic tetrapeptide with the sequence Ala-Glu-Asp-Gly. It is short, chemically simple, and surrounded by a literature that requires unusually careful reading.

Origin

Epitalon was developed as a synthetic counterpart to epithalamin, a peptide preparation extracted from bovine pineal gland. Extract-derived preparations are heterogeneous by nature, and one motivation for producing a defined synthetic sequence was to have a single characterised molecule to work with. The two are not interchangeable in the literature, and papers on epithalamin should not be cited as evidence about epitalon.

Reading the evidence critically

A researcher evaluating this compound should be aware of several structural features of its literature, because they materially affect how much weight individual findings can carry.

Much of the primary work originates from a small number of affiliated research groups, and a substantial portion was published in Russian-language journals with limited indexing in Western databases. Independent replication outside that network is comparatively sparse. Some frequently cited reports are conference abstracts or review summaries rather than full primary papers with complete methods.

None of this establishes that reported findings are wrong. It does mean that the usual heuristic — a claim repeated across many citations is well supported — fails here, because repeated citation can trace back to a small number of original sources. The indexed literature is at PubMed; searching AEDG peptide surfaces additional records filed under the sequence abbreviation.

Analytical characteristics

At four residues and roughly 390 daltons, epitalon sits near the lower size limit for conventional peptide analysis. Two practical consequences follow.

Short, highly polar sequences retain poorly on standard C18 reversed-phase columns and can elute close to the void volume, where separation from small-molecule impurities is weakest. Analysts often use aqueous-compatible stationary phases or ion-pairing adjustments to address this.

The sequence also contains two acidic residues, making the peptide strongly anionic at neutral pH and highly water-soluble — convenient for reconstitution, but it also means counter-ion content can be a larger proportion of gross weight than for a longer sequence. That is worth accounting for when converting a vial weight into a molar concentration; see net peptide content explained.

Sourcing

Because the sequence is short and inexpensive to synthesise, quality varies widely across the market. Identity confirmation by mass is the single most useful item on a certificate for a peptide this small. Product page: Epitalon 10mg.

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